Con Coughlin is the Telegraph's Defence Editor and a world-renowned expert on global security and terrorism issues. He is the author of several critically acclaimed books. His new book, Churchill's First War: Young Winston and the fight against the Taliban, is published by Macmillan in London and Thomas Dunne Books in New York. He appears regularly on radio and television in Britain and America.

Al-Qaeda will be rubbing its hands with glee over the persecution of John Yates

The members of the Home Affairs committee at the Commons have clearly had a lot of fun today interrogating Scotland Yard's John Yates over the failure of the Metropolitan Police to investigate fully allegations of the News of the World's involvement in phone-hacking when they were originally made.

After all the humiliation MPs have suffered at the hands of the police over the expenses scandal, which has seen several of their colleagues receive lengthy jail terms, you can understand their enthusiasm for turning the tables and making the boys in blue sweat a little under the interrogation spotlight.

But by focusing their attentions on Assistant Commissioner Yates, they are overlooking one vital fact. Mr Yates has a rather important day job, namely making sure that Londoners are kept safe from the diabolical plots of Islamist terror groups.

As head of the Yard's counter terrorism branch, Mr Yates is responsible for monitoring the activities of al-Qaeda and its affiliates, particularly after they have vowed to launch revenge attacks against Britain in retaliation for the killing of Osama bin Laden by American special forces in May.

Certainly the fact will not be lost on al-Qaeda and other Islamist terror groups that the man responsible for foiling their plots is currently pre-occupied with a very different form of criminality.